Fall 2012

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark

December 18, 2012

Mistletoe: A custom from the yules of yore

Aching for an excuse to kiss someone at a holiday party? Try luring him or her underneath a cutting of mistletoe. If the sprig is bearing fruit, magic happens. After the smooch, tradition requires the kisser to remove one translucent white berry from the sprig.

But what to do with a mistletoe berry?

Don't eat it. Although less toxic than the leaves, eating several berries might make you sick, inspiring your digestive system to ship them on a fast track out of your body. That's what happens with some birds, which swallow the fruit and quickly deposit the seed on the branch of a neaby tree — accompanied by a splash of fertilizer.

Even after passing though a bird, a mistletoe seed retains its sticky, mucilaginous coating, which cements the seed to tree bark. If it sprouts next year, modified roots will penetrate the tree's vascular system, from which the mistletoe will draw water and nutrients.

Ancient observations of the poop-on-a-stick origins of the plant led to its name "mistletoe," or mistiltan in Old English, derived from the Anglo-Saxon words mistel, meaning "dung," and tan, meaning "twig."

But on this side of the Atlantic, mistletoe was once used to counteract fertility. Native Americans employed the muscle-contracting medicinal properties of the plant to induce abortions.

Modern medical studies of American mistletoe indicate that extracts from the plant are toxic to certain cancer cells in mice and can enhance aspects of the mouse immune system that will slow the growth of some tumors.